emeric i wonder if you could do a quick calculation for me regarding powder capacity.

the hypothetical cartridge is 36mm long with a base diameter of 10.2mm.  case length is 27.5mm/

bullet is a 4.65mm which is very long - ideally 24-25mm.  its a neckless case with a super wide/flat shoulder to boost powder capacity

obviously the long bullet reduces powder capacity. but roughly how much capactity do you think it would have compared to 4.6x30?

i was hoping the round could reach .40S&W energies from a 1911 legnth barrel

You will need to develop a special process to load this cartridge, with a horizontal rotating press in order to seat the bullet while rolling the cartridge...

Anyway, the case volume should be 25-26 grs (without bullet) which is substantially higher than the 4.6x30 mm, but the extreme difference between the case diameter and the bullet diameter is not going to make it a "volume efficient" round, and it's going to be a waste of powder with a 5 in. barrel.

thanks. the HK4.6 has a 15mm bullet, and mine is 24mm, so i assume the final powder capacity would be no higher than 4.6HK.

i was hoping for a compromise pressure of 70k, and the weapon is basically a more compact MP9, similar size to a B&T USW.

do you think such a weapon could handle these pressures